[brerbear]

I have a Macbook Pro and an iMac computers each with a different iTunes Library which I want share. Both computers are running under Snow Leopard.
They are set up with a SpeedTouch router (ST585v6) inputting via an ethernet connection to an Airport Extreme. This is wirelessy connected to the two Mac computers. The system works fine with all files and external hard drives being read and accessed by both computers except in one instance, namely the iTunes folders.

I can share iTunes from an iMac to a MacBook Pro with no problems. However, when I want to share from the MacBook Pro to the iMac it does not work and I get the error message 'the shared library is not responding (-3529). Check that any firewall software running on either the shared computer or this computer has been set to allow communications on port 3689'.
I have spent over 4 hours with Mac Support who have found no software problems in either machine and have demonstrated that the two computers, when hard wired together by ethernet, function totally correctly. Also when the SpeedTouch router (supplied by AOL) is disabled and the Airport Extreme is hardwired into the MacBook Pro the iTunes inter operability between two machines is totally normal. BUT once the SpeedTouch is connected the fault comes back. The SpeedTouch ST585 v6 software is standard 6.2.29.2.
To my mind it is 99.99% certain that the SpeedTouch is causing the problem. I have disabled the firewall in the router to no effect and also put the router into bridge mode, again with no noticeable improvement. I am now at the point where I do not have the expertise to resolve this problem

[brerbear]

Should provide key additional information . The two Macs have their firewalls switch off therefore conclude reference in error message applies to the SpeedTouch roter.

[turtle777]

Do you have by accident both the router and the AE set up as DHCP servers ?

Why do you use that SpeedTouch router at all ?
Or is it a router and modem in one ?

-t

[brerbear]

The SpeedTouch is both a Router and a Modem and I not been able to find a way to configure it as just a modem. WHislt I have found it necessary to connect it via eathernet to the AE it does not seem possible to disconnect the wireless link which may be interacting with the AE but I have yet to find a way to prove this.

Although the DHS in put is into the SpeedTouch as you will appreciate I cannot therefore know for certain if the router and the AE are inadvertently effectively both set up as DHCP servers and the cause of the conflict. It just seems strange that iTunes can be read in one direction but not the other and if this was causing the conflict to my mind this surely would manifest itself in both directions.

[Cold Warrior]

Use Airport Utility to put your AE into bridged mode.
Open Airport Utility, click your AE from the left column, click Manual Setup.
Now choose Internet > Internet Connection > Connection Sharing: (Off) Bridged Mode.
This stops your AE from acting as its own DHCP server.

[brerbear]

I have done what Cold Warrior suggested but still have the problem.